The missiles struck a compound in Mangrothi village in the Shawal area, along the border dividing the North and South Waziristan tribal regions, the two officials said, speaking on condition of anonymity because they were not authorized to release the information.

Many Pakistanis oppose U.S. drone strikes because they say the strikes kill large numbers of innocent civilians — something the U.S. denies — and end up breeding more extremism by those seeking retribution.

The country's new prime minister, Nawaz Sharif, who was sworn in on Wednesday, has lashed out against the U.S. drone program.

During his campaign, he sometimes criticized the U.S. and its policy of using drones to kill militants in the tribal areas of Pakistan. Speaking to parliament earlier this week, he once again called for an end to the drone policy.

"This daily routine of drone attacks, this chapter shall now be closed," Sharif said to widespread applause. "We do respect others' sovereignty. It is mandatory on others that they respect our sovereignty."

Sharif gave few details on how he might end the strikes, however.

The U.S. considers the drone program vital to battling al-Qaida and other insurgents who use the tribal areas of Pakistan as a safe haven.